The violence broke out when the Kurdish Islamist group Huda-Par refused to allow members of the People's Democratic Party (HDP) to hold an electoral meeting in Kozluca village, located in the majority Kurdish Sirnak province, Dogan news agency said.
Zaman newspaper said a clash broke out "after the HDP members left the village without campaigning".
A man opened fire, wounding eight people, two of them critically, the official Anatolia and Dogan news agencies said.
Violence frequently breaks out between the pro-Islamist Huda-Par and HDP members, who are seen as close to the outlawed Kurdistan Workers' Party (PKK).
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In October and December last year, clashes between the two groups in southeastern Turkey left several dead.
The campaign leading up to the June 7 parliamentary vote has been marred with violence, mostly targeting the HDP.
Last week, two blasts targeting the party's headquarters in the southern cities of Adana and Mersin injured several people.
Should the HDP pass the 10-per cent threshold needed to have MPs in parliament, it would become more difficult for President Recep Tayyip Erdogan to reach his goal of changing the constitution to boost presidential powers.